1. Field of the Invention
The present invention relates to a method of manufacturing a branching pipe, which is used for a fuel filler pipe of automobiles or a water pipe and has a sub pipe branched off from a main pipe.
2. Description of the Related Art
A known branching pipe is a fuel filler pipe for automobiles as disclosed in JP No. 2001-96054A. The fuel filler pipe has a filler pipe main body, which connects a filler neck with a fuel tank and has a branching portion. A breather pipe is connected with the branching portion by press fitting or thermal welding. This prior art technique, however, increases the number of parts and requires assembly of the respective parts, thus undesirably increasing the manufacturing cost.
Another known technique of linking two pipes simultaneously forms a first pipe and a second pipe by blowing as disclosed in JP No. 7-214645A and No. 5-24101A. The blowing method, however, has difficulties in forming a complicated curved shape and is not suitable for continuous molding. This undesirably lowers the productivity and increases the manufacturing cost.